Similarly, there was no benefit in the prevalence of xerostomia following the use of recombinant human epidermal growth factor oral spray versus placebo [32], intravenous palifermin during chemoradiotherapy with cisplastin [33], melatonin gargle combined with metatonin capsules versus placebo [46], a viscosity-reducing mouth spray versus an equivalent physiological saline solution [48], and N-acetylcysteine rinse versus a placebo rinse after 3 months [57]. This evidence concerns the gene EGF and xerostomia.